Town officials have said the water meets health standards and is safe to drink, but the water–which comes out in colors ranging from yellow to dark brown–has alarmed residents.

“I urge you to interact with the town of Norton, Massachusetts and the Commonwealth to ensure that the water does indeed meet health standards, and further provide assistance in confidently determining the exact cause of the discoloration,” Warren wrote in a letter to the EPA.

Penny Heida fills her tub with dirty water (WBZ-TV)

Norton’s water comes from town wells, and high iron and manganese cause the discoloration–especially when the town flushes fire hydrants to clear the pipes.

“The MassDEP informed us that the system is in compliance with all health-based drinking water standards,” the EPA said in a statement. “EPA will continue to work…to ensure that public health is protected as this situation is resolved.”

Residents told WBZ-TV that the brown water has been costly, and caused them to have to replace dishwashers and washing machines.

The town is building a new treatment plant to deal with the issue, but it won’t be completed for another two years.

“It’s horrible. It’s nasty. It looks like coffee. You can’t see the bottom of the tub,” resident Penny Heida said.

Sen. Warren urged the agency to work with the town to get rid of the discoloration, writing, “The residents of Norton deserve nothing short of absolute confidence in the quality of their drinking water.”